Absolutely, a good mag is very reliable. In my case i did not have a good one.I suppose those with original dynamos trust Mr Miller dynamo more than Mr Lucas Mag what could be described as Hobson's choice
When I fitted mine, I removed the primary cover then used a rod to find TDC, marked the (inner) part of the rotor. Then attached a thin wire with a screw on the case and lined up with my first mark then marked the rod to find the BTDC and marked the rotor again. Line this mark up with the wire and you can fit the rotor. I checked my settings a few times before I was happy to fit the new rotor. I then fired up the bike and set with a strobe light making sure the marks lined up on full advance. It is a bit of a faf but works ok.Looks like I’m going to need to use a strobe to time up the thorspark. I’ve always used a rod down the bore to measure piston position to time the mag but that’s not going to work here
Any thoughts on where I can get a timing mark onto a comet? Best I can think of is run it without primary cover, and mark up the front pulley. Anyone got a better idea?